The Children's Cancer Center at St. Louis Children's Hospital, Washington University School of Medicine, is one of the 40 institutions and 24 affiliate institutions of the Pediatric Oncology Group who have pooled their patient resources and scientific expertise to study the natural history of childhood cancer, develop and compare effective therapeutic regimens and investigate the toxicity and effectiveness of new anticancer agents in the treatment of children with cancer. The investigators at Washington University include pediatric oncologists, radiologists, radiation therapists, neurologists, surgeons, and pathologists. All children with malignant disease are placed on cooperative group protocols if they are eligible, after informed consent is obtained. Data that is accessioned at the time the patient is placed on study protocol, during the study, and when off therapy is submitted to the Group statistical office for data analysis, interpretation and presentation. The investigators at Washington University serve in multiple administrative and research capacities for the group. The diagnostic studies, pathological findings, surgical procedure and therapeutic plan for all new patients and patients who relapse are discussed at the weekly Tumor Board Conference. Access to intensive multimodal therapy and experiment compounds is facilitated by the close contact of the center with the nearby Pediatric Oncology Group Operations Office, of which the Principal Investigator is Group Chairman. The acting principal investigator directs the effort whereby Washington University investigators review spinal fluid slides of all pediatric oncology patients to confirm the diagnosis of central nervous system leukemia, and the laboratories of two other investigators serve as Pediatric Oncology Group reference laboratories for the study of neuroblastoma tumors for N-myc and N-ras oncogene inactivation, and for the establishment of lymphoblastoid cell lines from patients so studied.